Train-control system



Nov. 19, 1929. c. s. BUSHNELL TRAIN CONTROL SYSTEM Filed March 1, 1927 mvzfoR Patented Nov. 19, 1929 UNITED STATES PATENT OFFICE CHARLES S. BUSHNELL, OF ROCHESTER, NEW YORK, ASSIGNOR TO GENERAL RAILWAY SIGNAL COMPANY, OF ROCHESTER, NEW YORK TRAIN-CONTROL SYSTEM Application filed March '1,

This invention relates in general to train control systei'ns of the intermittent inductive alternating current type, and has more particular reference to a system in which there is an acknowledging whistle and which has an improved acknowledging and reset means.

It is desirable, in systems of the character in question, to have acknow edging and reset means so protected that they cannot be interchangeably used to perform each others functions and it is desirable in connection with these means, to have an acknowledging whistle as well as other audible or visible means, for checking the proper Operation of the entire system, and for advising the en- ;rineman when it is safe to release the acknowledging contactor.

Vith the above and other objects in View, it is proposed, in accordance with this invention, to provide an automatic train control system of the kind referred to, which satisfactorily attains the various objects enumerated above.

lfurther objects, purposes, and characterfeatures of the invention will appear as the description thereof progresses, reference being had to the accompanying drawings, showing. solely by way of example, one physical form which the invention may assume. In the drawings:

Fig. 1 represents in a wholly schematic manner, one embodiment of the present invention.

Fig. shows, schematically, trackway controi means.

Referrin to Figure 1 of the drawing, there is shown a track comprising rails 1, divided, in the usual manner, into electrically insulated blocks by means of insulating joint 2. with a wayside signal 3 at the entrance to each block. The signals, as shown, are of the semaphore type, but could equally weil be of anv other type, such as color light, or position ight signals. As shown in a di nunuatic manner, (Fig. 2) each signal I, control; an adjacent inductor 4 positioned at the side of the track, by arm 3 open and close circuiting inductance coils 4 and a condenser "i the control being such that the doc is in an active condition, i. e., coils 1927. $ria1 No. 171,820.

4 and condenser 4: open circuited, when the signal is set at danger or caution while it is in an inactive condition, i. e., coils 4 and condenser 4 close circuited, with the signal set at clear. This is accomplished by means of circuits controlled by the signals as shown and including therein the inductance coils l and condenser 4 it having been deemed unnecessary to illustrate and describe this control in further detail, since it is not essential for a complete understanding of the present invention.

Carried on the car which is represented conventionally by means of axles and wheels 5, is a receiver 6, shown in the form of an H, but which might readily be of any other sultable design. Carried on the receiver 6 are two primary coils P, connected in series with each other and with a condenser 7, and a source of alternating current 8, shown as an alternator. The characteristics of the circuit including the primary coils are such as to tune this circuit to oscillate most freely at the frequency of the alternating current supplied by the alternator 8, which frequency is preferably relatively high, as of the order of about 360 cycles per second, for instance.

Also carried on the receiver 6 are two secondary coils S, which are connected in series with each other and with a condenser 9 and coils 10 of a main relay MB, in a circuit which is obvious from the drawing. As in the case of the primary coils, the circuit containing the secondary coils is tuned to oscillate most freely at the frequency of the alternating current supplied by the alternator 8.

The structure so far described operates in the following manner. \Vhen the receiver 6 passes over an inductor 4. without touching it as is usual in inductive train control systems, as is well understood by those skilled in this particular art, if the inductor 4; be in its active condition, it will so efiect the flux dis tribution in the receiver 6 as to reduce the induced current flowing in the secondary coils S, to zero, or at least sufficiently, depending upon the air gap between the inductor and receiver, to de-energize the coils 10 of the main relay MR. On the other hand, if the particular wayside signal in question be set at clear, the inductor is then in its inactive condition, as explained above, and has no eil cct whatever on the receiver, or else has the effect of actually increasing the amount of current flowing through the secondary coils S so that under such conditions, the relay MB is operatively unaffected.

The particular manner in which the flux distribution in the receiver is controlled by the inductor not explained in detail, as it is quite unnecessary for a complete understanding of the present invention.

The relay MR has its coils 10 on a mag netic core 11 which is preferably a laminated structure, in order to cut down eddy current losses and the like, and has a pivoted arma ture 12, normally held in the attracted position shown, by means of the core 11., and biased in a clockwise direction, to move when said coils are deenergized, by means of a spring 13. Carried by the armature 12, are armature contacts 14 and 15, electrically insulated from the body of the armature by insulating joints 16.

Associated with the relay hill is a restoring relay RR, very similar to relay MR, but unlike MR, its energizing circuit is not tuned, and comprising coils 17 carried on a laminated core 18, together with a pivoted armature 19 biased in a clockwise direction by a spring 20 and carrying an armature contact 21 insulated from the body of the armature by means of an insulating joint 16. The armature 19 is arranged to have a. retarded drop-away, due for example to its connection, by means of a rod 22, to a dash pct 23. At the end of the armature 19, opposite to the contact 21, is an upwardly projected restoring pin 21, positioned in the path of rotation of armature 12 of relay MB, for a purpose to be described below.

The system down includes a device EPV, which may be an electro-pneumatic valve, ar ranged to be normally energized, and when (lo-energized to either initiate an automatic application of the brakes, or impose a minimum speed limit, or a gradually decreasing tapered speed limit, on the train, or to in any other desired manner impose av restrictive infiucnre on the movement of the train. The IIPV ha a, contact member which is held up when the device is energized, and drops away upon de-energization thereof.

A reset device Rae is included, comprising a manually operable rod 26 connected to con tact linger 2?, normally open, and 28, normally closed, or simultaneously moving such contact fingers to their reverse positions. This reset device is positioned so to be inacc ole for operation while the train is in motion, as for example, by having it accessible only from the ground, whereby to preent m suse of the device.

An acknowledging device, Ac]; included in stem= comprises a manually depressible rod 29, biased to an up 'ard position by a. spring 30, and carrying pins 31 and 32 for respectively controlling movable contact fingers 333 and 31. On depression of the rod 29 the contact 33 is moved to its lower position, by pin 81, while pin 32 releases contact finger 3 1- and permits a spring 35 to move finger 34c downwardly with a retarded action due to dash pot 36, so that linger 34 and its spring 34- do not break contact until the lapse of a predetermined time interval after depression of the rod 29, in the present instance preterably about .15 seconds.

There is also included in the system an audible signal, shown as a whistle valve lVV, which connected up to be energized at the proper time to furnish the proper indication.

In order to simplify the wiring diagram and the explanation, letters I and C have been used to indicate the positive and negative terminals of a source of energy such as a storage battery, generator, or the like, and while such source is here contemplated to be a d ct current source of energy, obviously ,iltll'lllfl current might under certain cir- .i sauces be equally well employed. In a like n'ianncr. while the relay MR has been shown and deacribed as energized by alternating current, it is likewise obvious that under certain circumstances, direct current co ld equally well be used.

The restoring relay HR is energized through a circuit be inning at a source C and including the two relay coils 17 in series, contact linger 11 and front contact of relay MR, contact linger and front contacts of EPV, o a source it. Thus its energization requires that the armature oi the main relay MR be in energized position, and that the EPV be energized.

()n a consideration i the structure described ahovc, and or the energizing circuit just traced for relay RR, it will be seen that upon dc-cnergization of relay MR, its armatzire 12 will be rocked in a clockwise direc tion, and thus break the energizing circuit for relay RR. This permits spring 20 to rock armature 19 of relay RR in a clockwise direction, against the action of dash-pot 23, to thereby force the pin 2 1 against armature 12 thus to restore armature 12 to energized position. Restoration of armature 12 to energized position completes the energizing circuit lor relay RR, provided EPV has not, in the meantime. become (lo-energized to drop Contact linger 25, and thus he armature 19 of relay RR is drawn back to its attracted position shown in the drawing. In other words, drop-away of relay MR causes dr0p away of relay BR, and drop away of relay RR restores the armature 12 of MR, and this in turn. under certain conditions, namely that EPV has remained energized, operates to restore the armature 19 of relay HR to its attracted positionv Furthermore, in the operation above considered, when armature 12 0'1 relay MR is retracted, a circuit is completed for energizing the whistle valve NV through a circuit heginning with a source C, the whistle valve, contact finger ll and hack contact of armature 12, wire 37, contact finger and front contacts or EPV to a source B. The energization, therefore of the whistle valve WV, requires that relay MR be retracted and that at the tlllifl, time El; be energized.

On retraction of either of the two armatures 12 or 1!), or hoth of them, of the interlocked relays Ml anal RE. the normal energizing circuit for EPV is broken with the result that a brake application, tor example, is incurred, and the stick contact of EPV drops awav. The normal energizing circuit referred to tor EPY includes a. source C, the EPV, contact linger and front contact 28 of reset device Res, contact finger and front contacts 15 0t armature 12, contact finger and lront contacts 21 ot armature 19, to a source B. In other words. the normal encrgizing circuit for EPV requires that the two armatures 12 and 19 be in their attracted positions and that the reset device he in its normal raised position as shown.

\Vhen opera ed, under certain restrictions. the acknowledging device Ac/i' operates to forestall an automatic hrake application, by preventing de-energization of EPV even though the relays MR {UK 13R drop away. This auxiliary acknowledging circuit for energizing EPV, is a stick circuit including a source of enetg ll, stick contact and front contacts 25 of E? contact finger and trout contact 34 and contact finger and hack contact 33 of Ac/r, the EPV, to a source C. It will he noted that this energizing circuit can he maintained for only a l mited time, since approximately seconds lirom the time the contact linger 3? makes contact, contact linger 34 hrcaks contact and since th se two contact lingers are in series in the circuit in question such circuit can he maintained for only approximately 15 seconds. It is therefore neces sar in order to fore tall a hrake application on passing a signal at danger or caution, to operate the acknowledging contactor Ack shortly hetore reaching the signal in ques tion. and to release it within a. period of 15 seconds. It the ac .owledging contactor he tied down, the iillfllflwlttlgiilg circuit will he roken after 15 seconds, the linger 3 1, and the train will be subjected to a. brake application upon pa sing and an active inductor.

Assume, for the purpose of illustration, rt the train passes a si al set at clear, in

.iich circumstances the 1H iuctor 4: is inactiv and has no intlueiu-e on the receiver 6, so that all the parts rcmain in the positions shown in the drawing. In these circum stances the EPV remains energized and no brake application is incurred.

Assume now that the train pa ses an inductor in active condition, that is, with the signal at stop or caution. In these circumstances, assuming that no forestalling action is taken by the enginenian, the relay MB is deprived of current so that its armature 12 is retracted, thus breaking the energizing circuit for relay HR at contact linger and front contact 14, and the energizing circuit for EPV at contact finger and front contacts 15, with the result that a brake application is incurred. and the stick contact drops away. Also armature 19 of relay RR drops away, thus permitting pin ill to restore the armature of relay MR to its attracted position in which it is h ld h current {lowing through the secondary windings 5% since by this time the receiver has pa sed the inductor.

The restoration of armature 12 does not howc er, complete the energizing circuit for relay RR since this circuit is broken at the contacts 97:. due to de-energization of EPV. Likewise the energizing circuit for the whistle valve NV is broken at the stick contacts hcfore it completed at the contact finger 4 and its hack contact, so that this signal not energ zed and does not sound.

lhnler the circumstances, the train cannot procee int the brakes are released, and the hrakes cannot be released until EPV is nergized. The aclmowledging cont/actor is powerless to re-energize EPV since the acknowledging circuit is broken at the ccntacts 25 and the only manner in which the normal energizing circuit for EPV can he completed is h energizing relay RR and thiscan he done only by ope ation of the reset device lice which is ina rih e while the vehicle is in motion. Accordinglv after incurring a. automatic brake application, the car must he brought to a stop, utter wh ch the engineman can operate the rese device to thereby complete an ener; .z ng circuit to! relay RR. said circuit incluoing a source ll, contact finger and back contact 27, coils 17 of relay RR, to a source C.

On restoring the reset device to its normal position the energizing circuit just described is broken at contact finger hy releasing Res. but due to the slow drop-away char acteristics of its armature 19, relay RR remains in picked-up position until the normal energizing circuit for IGPV comp eted through contact finger and front contact and the normal energizing circuit for BB is completed through contact finger and front contacts 25 of EPV, thus restoring all parts to their shown nor .ial po i .ons. ll'he: armature 19 is once up, even though the relav RR then he (lo-energized. the dash-pot. device 23 maintains this armature 19 in po ition to close contacts 21 for a period 0? time at least equal to the time required for closing reset contact 98 after release of les, plus he period of time required for closing contacts 25 of EPV, after EPV has been re-energized through the circuit including the reset contact finger 28.

In the operation described above, had the engineman depressed the acknowledging contactor A070 just before passing the active inductor, energy would have been put on EPV through the acknowledging circuit traced above, and thus stick contact 25 would have remained up. In such circumstances, relay MR would have dropped away to dc-cn ergize relay RR to thus break the normal energizing circuit for EPV. Armature 19 of relay RR would then have restored relay hill to attracted position, which in turn would then have completed the energizing circuit for relay RR at contact finger and front contact ll, it being remembered that due to the cknowledging circuit, the stick contact of EPV remained up.

During the operation just described the whistle valve \YV had its energizing circuit completed through contact linger 1st and its back contact, and this circuit remained completed during the time that the slow dropaway armature 19 of relay RR was dropping away. In other words, the duration of the sounding of the whistle valve depends on the time required for armature 19 to drop away sutliciently to restore the armature of relay MB to attracted position, and it it were not for the slow drop away feature of relay RR the whistle valve lVV would but a very short whistle, or possibly none at all.

The sounding of the whistle \VV checks the operation of the entire system and appriscs the enginelnan that an active inductor is being passed, and upon the audible signal becoming silent, the engineman knows that he can safely release the acknowledging contact or A070, since he has been advised thereby that he is sa tel past the active inductor.

If acknowledging were accomplished as is sometimes done by putting auxiliary energy on the main relay to hold it up, the above described opcration of the whistle valve could not take place and its desirable features would be lost.

With the structure and arrangement of parts described above, it is seen that the acknowledging and the reset devices are safeguarded & iinst misuse and that, with the interlocked i lays MR and RR, the restoration of relay i x to attracted position cannot operate to re-energize relay RR if, in the meantime, EPV has been de-energized, due to the fact that the ei'icrgizing circuit for relay RR passes through contact finger and front contacts 25 of EPV. This stick feature of the lQPV permits dropaway and restoring of the main relay armature to give the above described whistle signal without, at the same time, re-energizing EPV. Thus the very desirable feature of retention of the acknowledging whistle is obtained in conjunction with all the necessary safeguards a ainst misuse of reset and acknowledging devices in connection with this type of automatic train control.

The above rather specific description of one form of this invention has been given solely by way of example, and is not intended, in any manner whatsoever, in a limiting sense. Obviously, the invention can assume many different physical forms, a d is susceptible of numerous modifications, and all such forms and modifications, are intended to be covered by this invention, as come within the scope of the appended claims.

Having described my invention I new claim 1. In an automatic train control system, a uormally ci'icrgized tratiic responsive device, a normally ei'iergized restoring member therefor, operating when de-energized to physically restore said device, a normally energized brake applying device acting when deenerg zcd to produce a brake application, and a normal energizii'ig circuit for the brake applying device directly broken upon decnergization of ither the traliic responsive device or lut, restoring member.

2. In an automatic train control system, a normally e ergized traffic responsive device. a normally energized restoring member therefor, for mechanically acting on said tratiic responsive device, a normally energized brake applying device acting when de-cnergized to produce a brake application, a normal energizing circuit for the brake applying device directly broken upon de-energization of either the traflic responsive device or the restoring member, and a normal energizing circuit for the restoring member broken upon de-energization of the tratlic responsive device.

3. In an automatic train control system, a traffic responsive device, normally energized to attracted position, a normally energized restoring member therefor, a normally energized brake applying device acting when de-energizcd to produce a brake application, a normal energizing circuit for the brake applying device directly broken upon deenergization of either the traffic responsive device or the restoring member, normal energizing circuit for the restoring member broken upon deenergization of the traiiic responsive device, and means operative upon de-energization of the restoring member to mechanically move the traiiie responsive de- 'ice to attracted position.

4:. In an automatic train control system, a normally energized traflic responsive device, a normally energized restoring member therefor, a normally energized brake applying device acting when de-energized to produce a brake application, a normal energizing circuit for the brake applying device directly broken upon de-energization of either the traflic responsive device or the re- Ill) storin member, a normal energizing circuitfor the restoring member broken upon deenergrization ot the traffic responsive device, and means. including a front contact of the brake applying; device, for completing a temporary energizing circuit for such brake applying; device independent of the restoring: men'iber and the trallic responsive device.

5. In an automatic tram control system, a trallic responsive device normally energized to attracted position, a normally enerestoring member therefor, a normally re applying device acting when to produc a brake a' 'iplication, a normal energizing circuit for the brake appl device directly broken upon deeuergization of either the traiiic responsive device or the, restoring; member, a normal energ' zingr circuit for the ref-d'oring member broken upon de-encrgization oi the tral'iic responsive device, means operative upon deenergization of the restoring member to physically return the "railic responsive de vice to attracted position, and means, includng a front contact ot' the brake anplying; device, for completing a temporary energizing circuit for such device, independent of the restoring member and the re ponsive device.

(3. in an automati train control system, a traillc re ponsive device, a restoring mem ber thereto-r, a brake applying device acting when dc-cne 'zed to produce a brake application, an energiz ng circuit for brake applying; device broken upon de-micreization ot either the trafiic responsive device or the restoring member, an QllQl'gl' 'ircuit for the restoringmember broken upon de-energization of the traflic responsive device, and reset means operable to complete an an:-;iliar v energizing circuit for the restoring member independent of the traliic responsive device.

7. in an auton'iatic train control system. a trallic responsive device normally in attracted position, a. restoring member therefor. a brake applying; device acting when ceencrgizod to produce a brake application, an energizing circuit for the brake applying device broken upon deener;,yization of either the tratlic responsive device or the restoring member, an energizing circuit tor the restoring member broken upon de-cncrgization of the tratlic responsive device, means operative upon de-enerzjization ot the restoring member to return the trallic responsive device to attracted position, and reset means operable to complete an auxiliary energizing circult for the restoring member independent of the tratlic responsive device.

8. In an automatic train control system, a irallic responsive device normally energized to attracted position, through a tuned circuit. by alternating current. a restoring member there tor normally energized with directcurrent, a normally energized brake applywhen tie-energized to pr0 ing device act mg duce a brake application, a normal energizing circuit for the brake applying device broken upon (e-energization ot either the trallic responsive device or the restoring member, a normal energizing circuit for the restoring n'iember broken upon deenergizalion oi the trallic responsive device, and means operative upon de-enere ization of the restoring' member to return the trallic resoonsive device to attracted position.

9. In a train control system, a normally energized main relay, a normally cnergz ized restoring relay therefor, means operable on release of the main relay to cause the restoring relay to restore the main relay to attracted position, a stick brake applying device initiated upon de-energization ot the main relay, acknowledging means to temporarily prevent initiation of the brake applying device, and an acknowledging whistle energized throrm'h a circuit including: the stick contact of the brake device and a back contact of the main relay.

10. In a train control system, a normally energized main relay, a normally energized restoring relay therefor, means operable on re 0 of the main relay to cause the restoring relay to restore the main relay to at tracted position, a stick brake applying device initiatid upon de-energization of the main relay, acknowledging means to temporarily prevent initiation of the brake applying device, an acknowledging: whistle energized through a circuit including the stick contact of the brake device and a back contact of the main relay, and means causing slow drop away of the restoring relay armature.

ll. In a train control system, a main relay, a restoring relay therefor. means operable on release of the main relay to cause the restoring relay to restore the main relay to attracted position, a stick brake applying device initiated upon de-energization of the main relay, acknowledging means to temporarily prevent initiation of the brake applying device by completing a stick energizin circuit for the brake applying device, and an acknowlec ging whistle energized through a circuit including the stick contact of the brake device and a back contact of the main relay.

12. In a train control system, a normally energized main relay, a normally energized restoring relay, means operable on release of the main relay to cause the restoring relay to restore the main relay to attracted position, a stick brake applying device initiate upon de-energization ot the main relay, and also upon de-eneraizatien of the restoring relay, reset means for the restoring relay. acknowledging means to temporarily prevent initiation of the brake applying device, and an acknowledging Whistle energized through a circuit including the stick contact of the brake device and a back contact of the main relay.

13. In an automatic train control system, a firs.u relay having an energizing circuit responsive to trallic conditions, a second relay energized throng-5h a circuit including a front contact of the first relay, and means, for mechanically moving the arn'iature of the first relay to attracted position, operative upon (lecnergization of the second relay.

I l. In an automatic train control s Sl'tlll, a first relay riaving an energizing circuit responsive to trallic conditions, a second relay energized through a circuit including a front contact of the first relay, means to mechanically move the armature of the first relay to attracted position upon dc-energization of the second relay, a stick brake device initiated on de-energization either of id relays, and a whistle valve enei zed through a circuit including a back contact of the first relay.

1?). In an automatic train control system, a first relay lnxving an energiz ng circuit re sponsive to trallic condilioi'zs, a second relay energized through a circuit including a front contact of the hr rel y, means to mechanically move the armature of the first relay to attracted position upon deener 'zation of the second relay, a stick brake device initiated on de-energ zation of either of said. relays, and a whistle valve energized through a, circuit including back contact of the first relay and the stick contact of the brake device.

16. In an automatic train control system, a first re ay having an energizing circuit responsive to trailic conditions, a second relay energized through a circuit including a front contact of the first relay, means to mechanically move the armatiu'e of the first relay to attracted )osition upon de-energization of the second relay, a stick brake device initiated on de-cnergizathm of either of said relays, a Whistle valve energized through a circuit including a back contact of the first relay and the stick contact of the brake device, and means to cause an appreciable time delay be tween de-energization of the first relay, and restoring of the first relay armature to attracted position.

17. In an automatic train control system, a first relay having a tuned circuit energized with al ernai' ing current, a second relay energized with d rect current through a circuit includi a f ont contact of the first relay, and means, operative on de-energization of the second relay, for mechanically moving the armature of the first relay to attracted position.

18. In an automatic train control system, a first relay having an energizing circuit supplied With alternating current and tuned to oscillate most freely at the frequency of said alternating current, a second relay energized 'ith direct curl .nt through a circuit including a front contact of the first relay, means,

operative on de-energization of the second relay to mechanically move the armature of the first relay to attracted position, and a brake applying device directly initiated by the release of either of said relays.

19. In an automatic train control system, av first relay having an energizing circuit supplied with alternating current and tuned to oscillate most freely at the frequency of said alternating current, a second relay energized with direct current through a circuit including a front contact of the first relay, means, operative on de-energization of the second relay to mechanically move the armature of the first relay to attracted position, and a brake applying device initiated by the release of either of said relays.

20. In an automatic train control system, a trallic responsive device normally in attracted position, a restoring member therefor, a brake applying device acting when deenergized to produce a brake application, an energizing circuit for the brake applying device broken upon de-energization of either the lralhc responsive device or the restoring member, an energizing circuit for the restor ing member broken upon de-energization of he traflic responsive device, means operative upon de-energization of the restoring member to restore the trallic responsive device lo attracted p sition, and reset means operable to complete an auxiliary energizing circuit for the restoring member.

2i. In a train control system, a normally energized main relay, a normally energized restoring relay therefor, means operable on release of the main relay to cause the restoring relay to move the armature of the main rel to attracted position, a brake applying device initiated on deenergization of the main relay, stick means associated with, and making a stick device of, said brake applying device, acknowledging means to temporarily prevent initiation of the brake applying device, and an acknowledging whistle energized through a circuit including a contact on said stick device and a hack contact of the main relay.

In an automatic train control system, a normally energized trafiic responsive device, a normally ene gized restoring member therefor operable when de-energized,to physically restore said device, a normally energized brake applying device acting when deenergized to produce a brake application, and a normal energizing circuit for the brake applying device broken upon de-energization of either the tralfic responsive device or the restoring member.

In testimony whereof I alliX my signature.

CHARLES S. BUSHNELL.

S Tl 

